December 10, 2012 -- Scientists from VIB, KU Leuven, UGent and Harvard have succeeded in reconstructing DNA and proteins from prehistoric yeast cells. This made it possible to determine how genes developed and evolved into their current form over more than 100 million years.

Kevin Verstrepen (VIB/KU Leuven): “These results provide answers to an argument frequently used by opponents of the theory of evolution: the chance of the occurrence of a new characteristic –a functional new segment of DNA – from scratch is similar to the chance of a modern jumbo jet assembling spontaneously from a few pieces of scrap metal… Many scientists have proposed that the new functional DNA does not appear out of thin air, but is built up gradually from a copy of an existing segment of functional DNA. By reconstructing a piece of prehistoric DNA that was copied several times during evolution, we were able to investigate the changes that occur in each of the copies and which gradually lead to new functions.”

Characteristics from nothing

An important unanswered question in Darwin’s theory of evolution is how new characteristics seem to appear out of nowhere. Such innovations appear to contradict the principle of gradual change, in which existing characteristics slowly evolve into another form. Yet we know that may “inventions” took place during the evolution of life.

We do not know which processes form the basis of this "evolutionary innovation". One of the biggest problems is that virtually no prehistoric DNA sequences or proteins have been conserved, so that it is not possible to examine how these ancient versions differ from the current versions. This prevents us from understanding how new sections of DNA and new proteins developed.

Rebuilding prehistoric DNA and proteins

Using a combination of the latest techniques in biology, the scientists Karin Voordeckers, Chris Brown and Kevin Verstrepen from VIB in Leuven, together with Steven Maere (VIB/UGent) succeeded in rebuilding the DNA and proteins of prehistoric yeast cells.

Steven Maere: “We used sequence reconstruction algorithms to predict the DNA sequence of ancestral genes from dozens of present-day DNA sequences. This enabled us to rebuild the corresponding ancestral proteins.”

Karin Voordeckers: “We searched very specifically for how the yeast adapted to break down various sources of sugar. We found that the primal gene that codes for the protein for the digestion of maltose – a sugar in grain – was copied a number of times during evolution. The DNA of some copies changed slightly, resulting in new proteins that could break down different sugars. By modeling these changes in the corresponding proteins, we now understand how just a few changes in the DNA can lead to the development of new activity in the corresponding proteins”

The scientists think that this type of duplication of the DNA often forms the basis of the emergence of apparently “new” proteins. In other words: the jumbo jet is gradually built from a copy of an existing airplane.

VIB

VIB is a non-profit research institute in the life sciences in Flanders, Belgium, with 1200 scientists conducting strategic basic research on the molecular mechanisms that are responsible for the functioning of the human body, plants, and micro-organisms. Through a partnership with four Flemish universities – Ghent University, the Katholieke Universiteit Leuven, the University of Antwerp, and the Vrije Universiteit Brussel - and a solid funding program, VIB unites the forces of 72 research groups in a single institute. Through its technology transfer activities, VIB strives to convert the research results into products for the benefit of consumers and patients. VIB develops and disseminates a wide range of scientifically substantiated information about all aspects of biotechnology. For more information, please visit www.vib.be.

Ghent University

After more than twenty years of uninterrupted growth, Ghent University is now one of the most important institutions of higher education and research in the Low Countries. Ghent University yearly attracts over 30,000 students, with a foreign student population of over 2,200 EU and non-EU citizens. Ghent University offers a broad range of study programs in all academic and scientific fields. With a view to cooperation in research and community service, numerous research groups, centers and institutes have been founded over the years. For more information www.UGent.be.

KU Leuven

KU Leuven, founded in 1425, is Belgium’s largest university. As a leading European research university, it offers a wide variety of academic programmes in Dutch and English, nurtured by high quality interdisciplinary research, both at the university and at its internationally acclaimed university hospitals. More than 6,000 researchers from over 120 countries participate in curiosity-driven and strategic frontier research, as well as targeted and demand-driven research. The university’s interaction and co-operation with external partners is very intense. As a comprehensive university, K.U.Leuven offers 3-year Bachelor’s and 1 or 2-year Master’s programmes in almost all disciplines. The Leuven doctoral schools organise the international PhD tracks of close to 3,500 doctoral students. More information: www.kuleuven.be.
www.kuleuven.be..